Field of the Invention
The present invention relates to an organic light emitting display device and a fabricating method thereof.
Discussion of the Related Art
With the advancement of information society, a demand for a display device for displaying an image has increased in various forms. Recently, various flat panel display devices such as a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting display device have been used.
Of the display devices, the organic light emitting display device which is a self light emitting display device is more excellent for a viewing angle, a contrast ratio, etc. than the LCD, and may be fabricated at a lightweight and slim size and is favorable in view of power consumption as it does not need a separate backlight. Also, the organic light emitting display device is favorable in view of direct current low voltage driving, a fast response speed, and especially a low fabricating cost.
The organic light emitting display device is fabricated by several processes including, e.g., forming a thin film transistor layer on a substrate, forming a planarization film for planarization on the thin film transistor layer, forming an organic light emitting diode layer, which includes an organic light emitting diode, on the planarization film, wherein the organic light emitting diode includes an anode electrode, an organic light emitting layer and a cathode electrode. An encapsulation layer, which includes multilayered organic and inorganic films, is formed on the organic light emitting diode layer to protect the organic light emitting diode and the cathode electrode from oxygen and water.
The planarization film may be formed of a resin such as photo acryl and polyimide. If the planarization film is exposed to the atmosphere, since the planarization film absorbs water, water inside a vacuum deposition equipment is removed before the substrate provided with the thin film transistor layer is loaded into the vacuum deposition equipment during a process of depositing the planarization film. However, in spite of this effort, water may remain in the planarization film. For example, if water of a minute amount of 150 ppm exists in the planarization film, the organic light emitting diode or the cathode electrode may be damaged by outgassing generated in the planarization film. In this case, a problem may occur in that a pixel of the organic light emitting diode or the cathode electrode damaged due to water is displayed as a black spot.